## AESC: Lithium-ion Batteries for Nissan-Renault’s Hybrids, PHEVs and EVs

##### 16 May 2008
 AESC uses a Mn spinel cathode material. Click to enlarge.

Nissan Motor, NEC Corporation, and NEC TOKIN Corporation formed the joint venture Automotive Energy Supply Corporation (AESC) in 2007 to develop and market lithium-ion batteries for hybrids, plug-in hybrids and electric vehicles.

With work on all three types of electrified platforms currently underway at Nissan and alliance partner Renault, AESC outlined its current and next-generation cell technology at the Advanced Automotive Battery Conference (AABC) this week in Tampa, FL.

AESC is currently producing laminated lithium-ion cells using a manganese spinel cathode material (LiMn2O4). The laminated structure, said Nobuaki Yoshioka, Senior Executive Vice President of AESC, enables the cells to have low electrical resistance. The large surface area supports high heat radiation, suited for large current charge and discharge.

The crystalline structure of the spinel provides stability and does not collapse in overcharging. The cells offer a high power density of more than 2,000 W/kg.

We have developed cells for HEV so far, but we are now developing a new concept for electric vehicles. EVs are a source of uncertainty [for drivers] for fear of running out of electricity and not being able to refill the tank. We will present that our EVs with the charging function of just a few minutes will provide the driver with an extremely efficient means of resolving the uncertainty.

—Nobuaki Yoshioka
Characteristics of the L3-10 and L3-3 Cells
Cell typeL3-10L3-3
Size (L x W x H) mm 251 x 144.2 x 9.2 251 x 144.2 x 9.2
Weight g 527 210
Volume mL 277 94
Capacity (1C) Ah 13 3.7
Nominal Voltage V 3.6 3.6
Energy density Wh/kg
Wh/L
89
171
63
142
Power density (2.5V) (25°C 10s @SOC50%) W/kg 2,060 2,250
Power density (1.8V)
(-30°C 2s @SOC50%)
W/kg 220 670
Performance High energy High power
Application EV HEV

AESC has its EV batteries under test in the Subaru R1e vehicles being tested in Japan by TEPCO; a quick charge (80% capacity of the 9.2 kWh pack in 15 minutes) is part of the vehicle specification.

AESC’s current EV battery is the L3-10, a 13 Ah, 3.6V laminated cell that uses the same footprint of the L3-3 cell. The material used in the L3-10 is the same as used for HEVs, but AESC thickened the electrode and increased the number of laminate layers to increase the capacity to 13 Ah.

The L3-10 has 3.5 times the capacity of the L3-3.

 Power characteristics of the L3-10 at 25°C. Click to enlarge.

The discharge rate characteristics of the cell are good because of its low resistance derived from the cell structure; the L3-10 shows high discharge power at a wide SOC range.

With the appropriate quick charge infrastructure, the L3-10 can be recharged to 90% SOC in 15 minutes, with a cell temperature increase of a maximum 8° C. The cell can reach 60% of capacity in 5 minutes.

Based on AESC’s testing, the cells will retain more than 80% capacity after 7 years, including 70,000 km (43,496 miles).

For the next-generation of EV cells, AESC is working on a new cathode material of a nickel-mixed Mn spinel and a graphite carbon anode. The cell will feature an enlarged footprint, but will be thinner to increase heat discharge, and have a capacity of 30 Ah.

With a capacity in excess of 30 Ah, we can cut the number of cells [compared to applications of the L3-10] in half.

——Nobuaki Yoshioka
 Fuel economy and vehicle speed by driving distance of a prototype Nissan PHEV. (Fuel economy in mpg, speed in kph.) Click to enlarge.

Also at the AABC event, Takeshi Miyamoto, Engineering Director, Electronics & Power Electronics Engineering Division, Nissan, said that the internal hybrid drive currently under development at Nissan for deployment in 2010 is a parallel hybrid system.

Nissan has also been testing a 40 km all-electric range plug-in hybrid (PHEV) with the laminated Li-ion cells, with significant demonstrated fuel economy improvements during the charge depleting mode, and fuel economy better than a conventional hybrid vehicle during charge sustaining mode. (See diagram at right.)

“The cell can reach 60% of capacity in 5 minutes.” Nice. So at night when the fare is low you can almost fill it up for $1.5 (30kWh at 5 cents). A cup of coffee will be more expensive and the envy of the gentleman next to you paying to fill up his old gasoline Hummer will be priceless ;-) I can’t wait to get my hands on one of these vehicles. They should not compromise with performance though. Make them fun to drive. "Based on AESC’s testing, the cells will retain more than 80% capacity could remain after 7 years, including 70,000 km (43,496 miles)" Which averages to about 6k miles annually. A monthly commute of 800 miles (40m/day*20days)= 9600m annually. Lifespan and cycles may be a little short but the fast charge benefit will attract some consumers. All in all another competent entry into the 2010 electrification Olympiad. Congratulations to Nissan. 80% of 9.2 kWh in 15 minutes (1/4 hour) is 29 kW. At 3.6 Volts that's over 8000 Amps, which is a huge amount of current and power any way you slice it - enough to power several houses at peak draws. All running through a cable you hold in your hand and attach to your car. I'd be curious to see what kind of hookup they have for the quick charge, how thick the cables are and so on. IMO... Quick charge will be done at higher voltage, lower current, so cable will not be thicker. P = ExI It will be a specialized piece of equipment at a charging station not at your house. You will slow charge from line voltage at your house over night. This is very good news from Nissan. They obviously are very serious about EV's and plug in EV's. It should be possible to do an automatic / robotic plug-in fill-up at an EV/gas station so that we don’t need to get out of the car and fumble with wires. Make a >standard plug< for high voltage quick charging and put it on a >standard place< on the car e.g. below at the front of the car. Let the car use a >standard way of communicating< what type of EV it is and how much power it can handle given the current state of the battery. You drive to a certain place roll down your window press a button for how many kWh you want and submit your credit card credentials. Of cause there should also be an option to get coffee, water etc now that you have the chance to get that as well. Personally I would not like to hold a high voltage cable in my hand while it rains and the wind is blowing. Much better to have it done by some kind of robot that can also be filled with sensors to check that the plug-in is done correctly and that the battery is charging according to plan. Worst case you could have an EV Hummer with a 70 kWh battery that needs to be filled by 60% in 5 minutes. That is 504000 Watts. Definitely not something I would like to hold in my hand even if I was told it was very safe. Looks like these Li-Ion batteries (Nissan/NEC and Mitsu/GS-Yuasa) don't like much cold weather. And therefore wouldn't be suitable for very cold winters (up to -30 deg Cels), at least these batts of first generation, just being announced. Tesla will be heating (in winter) battery compartment area. Another issue regarding BEVs is heating the interior of the vehicle, in cold weather (-5 Celsius and colder). It can drain significant amount of power (500 W or stronger heater), especially during a rush hour or a traffic jam, in very cold weather, when battery (if unheated) is weaker anyway, or needs to be heated itself. ? And what would be the most appropriate way of heating? Battery powered heater, or reverse cycle AC (they're just a little more efficient than electric heater below -3 deg Cels, or maybe inapropriate to use at all for some other reasons)? How about using some liquid fuel for heating interior (and battery pack if needed)? Liquid fuels are probably much more efficient when used for heating, than for providing mechanical power. Is there some liquid fuel that can be burned (for heating batteries and interior) without need for catalytic convertor (and still not exceed emission limits)? The heating issue in cold weather should not be a problem for range extended EVs since they can source the heat from the range extender. For a dam cool range extended EV see this video of Fisker’s Karma. Enjoy. http://www.youtube.com/watch?v=DPYUd9pLEKo @Hal: 80% of 9.2 kWh in 15 minutes (1/4 hour) is 29 kW. At 3.6 Volts that's over 8000 Amps For an actual HEV, they will combine the cells in packs. The cells will be connected in series, not parallel. An average HEV pack will have a voltage of around 300V, yielding a current of ~100A. That sounds a lot better. Well that heating issue will just mean it'll be a little longer before they hit us up in canada, but i guess that also means the technology should be a little more perfected by the time we get them. Regarding the heating issue, your car would be warm when you got to it in the morning if you'd kept it plugged in to recharge overnight and had set the timer. Beyond that, RAV4 EV users claimed that it didn't make much of a difference to range using the AC or the heater (which was an electrically powered heat pump). Quoth Hal: 80% of 9.2 kWh in 15 minutes (1/4 hour) is 29 kW. At 3.6 Volts that's over 8000 Amps The cells are 13 Ah each; a charge from 20% to 60% in 5 minutes would take 62.4 amps; the remaining charge from 60% to 80% in 10 minutes would take 15.6 amps. This is the total current; the battery will consist of cells connected in series, not parallel, and the voltage will increase. Quoth Henrik: Personally I would not like to hold a high voltage cable in my hand while it rains and the wind is blowing. Gold-plated solutions won't go very far. Why not keep it simple? You can keep voltage off the cable until you're not holding it any more with a little device called a "switch". Quoth clett: your car would be warm when you got to it in the morning if you'd kept it plugged in to recharge overnight and had set the timer. Just one more thing which makes the PHEV a better car. BTW, it looks like we're well on the way to that$6/gallon gas I predicted 3 years ago.

The Altairnano battery was certified by AeroVironment (CARBites - sorry Stas)for ten minute quick charge. They used a 250kw "grid connected" 220V 3Ph AV charger.

Henrick - no need for robots. This is what teenagers are for. 330V @ 100A does not flow until a safely established and tested connection is made. And the teenager is not creating a ground loop (i.e. not holding the cable.) Unless you want to cull teenagers...

ref: recharging batteries.

A proximity protection could easily turn (off) the charging high power until the driver/operator is at least x feet away (if really needed).

Of course, a common interlock will keep the power off until the plug is properly connected and a charging start warning is given.

Of course, commercial charging stations will have suffissant power for quick charges.

Slower overnight home charging with regular 110/220VAC is a non issue.

Why so much reluctance about something that is not even a challenge.

To improve ease of charging and economy a second battery
similar to the one in the vehicle could be kept at the owners residence. this could be charged slowly from solar panels and/or from the electrical supply. The in car battery could be charged from the stationary residential battery much in the same way as batteries are connected together for a Jump Start. For safety reasons this would require a specially designed connecting cord.To transferr 12KWH of energy at 240 volts on a 50Amp cable would take one hour.I think 12KWH
would be good enough for about 50klm.and the cost in Canada would be about $0.72. I cannot wait for this technology to become a reality and never have to buy gasoline again. The preceeding comments seem mostly to be making mountains of mole hills. The internal combustion engine of a plug in hybrid can provide more than ample heat for batteries in extreme cold as well as heat for passengers and/or torque for a vapor compression air conditioner. In serial hybrid mode the car will still get superb mileage and also preserve the ICE infrastructure. On the majority of commutes, most drives can easily run in all electric mode. PHEV is the way to go. A further reply to comments regarding charging by "solar panels and/or from the electrical supply"... Grid tie inverters already commercially proven add solar and/or wind to the electrical supply. There is no need for dedicated conversion. Solar power replacing units of utility power for EV or PHEV battery charging is roughly equivalent to$3/gallon gasoline. The marriage of PV with PHEV and EV can eliminate dependence on foreign oil and utility brown outs and black outs.

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